1.42. In the case of toluene as a surrounding medium Qext-spr
decreases from a relatively large value at tcoat ) 0by 11% for a
coating thickness of 4 nm and approaches a value of Qext-spr for
thicker coatings which is typical for an uncoated particle in a
medium having a real refractive index of 1.42. Similar behavior is
observed for ìspr, which increases with increasing tcoat when water
is the surrounding medium (solid line in Figure 9b) and decreases when toluene is the surrounding medium (dotted line in Figure 9b) to reach the same value for both cases at large coating thickness. This example demonstrates that the influence of a coating and of the surrounding medium on Qext and hence A cannot be neglected. As a result of that, the equations and/or the fit parameters derived here have to be modified for other dielectric environments.